This invention relates to such two-part tools, particularly milling cutters.
Divided milling cutters of the type to which this invention relates are utilized particularly in the wood working industry, e.g. for tonguing or grooving or alternatively simultaneous round-planing or bevelling of two opposing edges of boards and the like.
When boards of another thickness than previously are to be planed, one will have to change the distance between the first (upper) milling cutter half and the second (lower) milling cutter half. A traditional way of carrying out this operation (so called "setting") involves inserting or removing of a greater or smaller number of spacing washers, each having a greater or smaller thickness, between the two cutter halves. This setting operation is tedious and time consuming, since a plurality of bolts have to be unscrewed and tightened again, and it can not be carried out without previous removal of the milling cutter head from the cutter spindle. Another drawback resides therein that the distance adjustment can not be made step-less or continous.
Such divided milling cutters and similar two-part tools may be removably secured to a rotating spindle either by purely mechanical means or hydraulically. Examples of milling cutters of the first kind are disclosed in the Swedish Pat. No. 19595, the U.S. Pat. No. 987,391 to Mitchell and in my abovementioned U.S. patent application. An apparatus in which tools, such as cutter halves, may be hydraulically clamped to a rotational spindle froms the subject matter of the U.S. Pat. No. 4,244,248 to Adell et al. This apparatus comprises a double walled sleeve which is formed with means for providing a pressure in a recess formed between the outer wall and the inner wall of the sleeve and for releasing the pressure from said recess. One or more cutter halves or similar having center bores fitting the outer dimension of the sleeve are slipped onto the sleeve, whereupon the sleeve together with the tools are slipped onto a rotatable spindle, and a pressure medium inside the recess of the sleeve is pressurized, whereby the two walls of the sleeve are subjected to a radially inwards and outwards directed pressure providing some expansion outwards and inwards respectively of the said walls, whereby the sleeve, the rotatable spindle and the tools are interconnected. The tools are clamped between abutment means on axially opposite sides of the tools, spacers in the shape of distance sleeves being interposed between the tools and also between each tool and its adjacent abutment means. When the mutual distance between the tools has to be changed it is necessary to dismount the whole apparatus and substitute other distance sleeves for the previous ones. This substitution can not be carried out without removing the entire apparatus from the spindle.